1. FIELD OF THE INVENTION
The present invention relates to an electric plug contact which includes an electrically conductive contact body which is shaped to include an essentially cylindrical portion, and a spring sleeve which encompasses the cylindrical portion of the contact body, the cylindrical portion including anchoring projections and the spring sleeve including cooperating perforations. The present invention also relates to a method for the manufacture of such an electric plug contact.
2. THE PRIOR ART
Plug contacts of the type mentioned are known--see British Pat. No. 246,700 and Swiss Pat. No. 511,523. The contact body of the electric plug contact, which may be formed as a plug pin or as a plug sleeve, consists of an electric contact material, such as brass, copper, bronze, and it guarantees a low electric volume resistivity and a relatively high current capacity. Because of the relatively low elasticity of the contact material, the contact body may be connected in a simple manner by a squeeze or crimping connection to an electric conductor. The spring sleeve performs several functions. For one thing, it may be provided with outwardly extending tongues or flaps which permit the insertion of the plug contact into a housing of insulating material, yet will prevent the withdrawal of the plug contact from the housing due to striking against an inside shoulder of the housing. In addition, the spring sleeve may contribute to the prevention of deformation of the contact body, especially when the latter is rolled into pipe form from sheet metal material and thus includes a longitudinal joint. In the case of contact tongues formed by longitudinal slits, the spring sleeve may also function to prevent too great an outward bending of the contact tongues and/or to push the contact tongues resiliently toward the inside, i.e., in order to bring about a higher contact pressure on a contact pin introduced into the plug sleeve.
In the case of the hitherto known plug contacts of the noted type, the spring sleeve has been fixed on the contact body by flaps formed on the spring sleeve engaging with recesses in the contact body. This type of fixation is conditioned on the fact that in the case of the production of the plug contact, the spring sleeve is held in full contact with the periphery of the cylindrical part of the contact body, while the flaps are bent into the prepared recesses of the contact body. In order to make possible the bending of the flaps into the recesses of the contact body, the recesses in a direction transverse to the line of bending of the flaps must be considerably wider than the thickness of the metal sheet of the spring sleeve, i.e., wider than would be required considering only the terminal positions of the flaps. From this follows an undesirable weakening of the contact body. When the plug contact is a plug sleeve, the type of fixation used hitherto has the additional disadvantage in that the flaps of the spring sleeve must be relatively short so that they will not project into the inside space of the contact body intended for the reception of a plug pin, in which event the anchoring of the spring sleeve on the contact body is relatively uncertain, such that when the plug sleeve is used the longitudinal joint of the spring sleeve may possibly burst open. This, to be sure, could be avoided by interconnecting the parts of the spring sleeves themselves adjoining the longitudinal joint in a positive manner by making flaps on one portion of the sleeve engage with recesses in the other portion of the sleeve and by bending the flaps back. However, such a plug contact is more complicated in construction and more expensive to produce, and local enlargements of the outside dimensions of the spring sleeve develop due to the superposed portions of the spring sleeve and of the flaps, which in some cases is a disadvantage.
It is an object of the present invention to provide an electric plug contact which avoids the disadvantages of known electric plug contacts, as described, and wherein a perfect connection will be guaranteed between the spring sleeve and the contact body, without any flap-shaped parts of the spring sleeve projecting into the inside of the contact body and without enlarging the outside diameter of the spring sleeve by superposed portions of the sleeve. Furthermore, it is an object of the invention to provide a plug contact which can be produced in a relatively simple and economical manner. Finally, it is also an object of the present invention to provide an effective, relatively simple and economical method for the production of the plug contact, by which process a safe fixation of the spring sleeve on the contact body is made possible.